Tuesday, August 18, 2009

Sculpting 201: Pinning, Armature, and Large Shapes

Here we go again with another foray into learning to sculpt! You've seen the basics of sculptwork, but what if you want something that doesn't follow the shape of the original sculpt? Something that's not just a repair, but instead a little larger, a little more complex, a little more personalized? For this you need to step beyond the basics and into the intermediates. Wait! Don't run away! It's really not that difficult! Plus, I promise the bleeding will stop sooner than you'd expect...

Now one trick is that you're going to be making larger gaps between your original pieces. Putty is naturally a little flexible and will tear under stress. Even normal game play can cause this and it's even worse if you drop the fig or try traveling anywhere. It's foolish to rely on the putty to hold up by itself, especially on a model with metal pieces. The solution is simple: the humble pin drill.

What is a pin drill? Simply, a hand cranked drill for working with really small drill bits. Games Workshop has a decent one with silicone pads and 6x 1mm bits. Because I believe in the open market system, here's similar items from Ace Hardware, Gale Force 9, or Ehobby Tools.
Now I can't really point at one version or another and say "that is the best for everyone". You need to find the one that's right for you. But here's a few tips I can give on things to look for:
1. A swivel plate. This is the flare, knob, or pad at the base of the vise. A deep drill, hard metal or dull bit can require a bit of force to drill. The swivel plate allows you to push down the length of the drill with your palm or the base of your fingers. This takes strain and pressure off your finger tips. But even better, it gives you a firmer grip on the whole system, letting you focus on details like alignment and turning the drill. It's for this reason I recommend against the "Double Ended" version shown on Ehobby... long use can be painful.
2. Size. There's a bit of variance in the design of pin drills. Different makes have different lengths, circumference, or positioning of the pads. This is why I strongly recommend picking one up in person to get a feel for it. For example, the GW version just doesn't work for me because of where the pads are placed... it's designed for someone with smaller hands than my mitts.
3. Collets and bits. A collet is the technical term for the part of the vise that compresses to hold the bit in place. Simple systems like GW's have a limited collet and are designed for a very small tolerance of drill bits. Others will have 2 or 4 collet systems that allow a greater variance in bits. In the same sense, also take note of how many bits you get and how big they are. You WILL break bits. I tend to go through them almost as often as I do Xacto blades. A pro to the GW set is that you get 6x bits. A con is that they're all 1mm; which doesn't do you much good if you really need a .75mm.

So now that I've bored you to death with pin drills, you might be wondering why a drill will matter. It's easy and yet another great technical term... for making your armature.
Armature: Sculpture. a skeletal framework built as a support on which a clay, wax, or plaster figure is constructed.
Now if you're building an entire fig from scratch, then your armature can be built and sculpted over. But if you're modifying an extant mini, you'll need to build on into that. This is why a pin drill is so important. Other tools like a clamp, chisel blade knife, mini-saw, files, and other tools are nice... but only a pin drill can create the smooth bore you need for proper pinning and armature.

Simply, armature is the skeletal structure on which you build. It gives rigidity to the piece, allows you to get a sense for basic form and anatomy, defines your simple proportion, and gives you something to hang the putty on. Some people like staples or paper clips. Personally, I use sewing and quilting pins. Note: pins, not needles. Needles are made with a higher temper steel, so they're stronger and more firm but they also tend to snap rather than bend. Sewing pins provide the right amount of strength, rigidity, and poseability for what I like to do.

So the first step is simply to drill a hole into the fig at the place where the bone or other base framework should be. Then glue your pin in place. Bend it to the shape desired. The excess can be cut off, but sometimes it's nice to have it there to mount the fig for sculpting, painting or basing. If you're unsure, hold off... it's always easier to remove than to add back on.

Now that you have the basic skeleton of the piece ready, you can add basic "filler" mass to create your larger core shapes. This is technically more of the armature as you're just sketching out the basic shapes. It can be more metal, glue, putty or other filler material to bulk out the fig. Brown Stuff and other hard epoxies are great for this. You're not worried about detail here, so much as getting a basic shape on the fig against which details can be formed. Just remember that this layer should be slightly recessed from your final layer, that way you're not having to add more putty to blend the seams. For a great example on armature and building up on it, go check out Klaus' Dei Greci site. In particular there's this, this, and this post from his Ogryn in the armature stages.

One more thing to point out here is that you can always change your armature. Just note that it is easier to do this early rather than later. And as a last item, it's perfectly acceptable to drill entirely through a bit and mount it in the middle of an armature. Both of these methods can be seen on my Chaos lieutenant's legs, the left being the "before" test phase and the right being the final.

That's it for this time... Next week: "Sculpting 202: Layering" Hope you've enjoyed the show!


  1. Hey there, how do you get such clean cuts of your pewter pieces? And how do you keep the green stuff from sticking to your tools?


  2. At the time of the above figs I was still using a hobby saw and/or #13 blade saws. I used these for years and have a number of small scars on my fingers to prove it.

    If you're in the market for something to do cuts like this, I cannot stress enough the quality improvement with a jeweler's saw. They're sturdier, have finer teeth, and you can twist the orientation of the handle during the cut to cut neat angles or curves. It's head and shoulders better than the hobby saws.

    For lubricating tools I've tried a number of items... water, petroleum jelly, chapstick, cooking oil, etc. But the one I always come back to is cheap and always available: saliva. It's about as tricky as water to learn to work with, but doesn't have to be cleaned between layers or for painting.

  3. Huh that's cool, my buddy got me some tools back when he wanted me to do greenstuff work instead of 3d work for www.chapterhousestudios.com but me being a 3d guy wasn't very comfortable with it.

    In the past I've just used my fingers for all the green stuff and it kept leaving my finger prints on there. I'll have to try out some of your techniques, thanks for the post :D

  4. Very cool, thanks for the info. Someday I'll venture into sculpting, but it's not in me to do so right now. :)

  5. @CKR: Heh, nice promo. :-p (I don't mind though as you guys do nice stuff and I've referred a few friends your way.) If you don't mind me asking, what 3d do you use?

    As to fingers... tools make ALL the difference, even just a hobby knife. Once the putty starts to cure (ie 2-3 minutes), it becomes a real headache to remove finger prints due to the oil residue. Actually, the first pic on this page has an example of this. There's a small error at the bottom of the right sleeve just above the hand. I was able to get enough of it out that it wasn't worth covering over, but I can still see it... Nowadays I take a completely "tools only" policy once the putty is mixed.

    @Oni: Glad you got something from the read. If/when you do try, do share. Hopefully these articles can save you some of the initial pains...

  6. Well, my friend who runs the site has one guy who sculpts in green stuff. When he needs me to do some stuff I use 3ds Max, and he has a printer out in china I believe that will doing a rapid prototype(fancy word for printing in 3D) It's not as cost effective as green stuff however, but is nice if you want to get symmetrical work such as grating on a rhino door, and things of that sort.

    It also has a small problem with not being able to pick up as much detail as you can do with sculpts just because they can't print that small yet. But for me I love being able to push Ctrl-Z :D

  7. this was areally helpful piece, its given me the inspiration to finally try out some more complex green stuff. Which i need to complete my own seer council as i hate doubling up on models.